Yamakura T, Okamoto I, Okada T, Tokashiki K, Tsukahara K.
In vivo (Athens, Greece) · 2026
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Abstract
Background/aim Head and neck photoimmunotherapy (HN-PIT) using cetuximab sarotalocan sodium requires post-treatment assessment for photosensitivity, but tests using direct sunlight are affected by weather and lack standardization. This study evaluated a simplified artificial irradiator for more consistent light irradiation testing. Patients and methods This single-center retrospective study analyzed 16 HN-PIT treatments in 8 patients with unresectable locally advanced or recurrent head and neck cancer. On days 6-7 post-treatment, patients underwent both direct sunlight exposure and a simple irradiation test using a FLASH-PAK projector equipped with an R-60 filter to evaluate reactions around the clinically relevant 690 nm wavelength. Erythema and edema were assessed on the day of the test and 1 month later. Results No photosensitivity reactions occurred with either method, nor were delayed reactions observed. Conclusion The simplified irradiator allows standardized, weather-independent photosensitivity testing after HN-PIT, although further studies are needed to confirm sensitivity and long-term reliability.